Method of making friction clutch elements



June 23,1936. s. w. EMRICK V 7 METHOD OF MAKING FRICTIQN CLUTCH EL EMENTS Original Filed May 5, 1934 INVENTOR Grams/V [MR/0r ATTORN Patented June23, 1936 UNiT-ED STAT 'rnon or MAKING FRICTION ELEMENTS George W. Emrick, Brooklyn, 11. Y.

7 Original application May 5,

Divided and this application July 12,

724,110. 1935, Serial No. 31,020

"12 Claims. (01. 192-101) This invention relates to the method of constructing clutch devices and particularly to the facing, friction or gripping surface thereof; and the object of the invention is to provide a clutch, the face of which is composed of suitable fibrous material, such for example as asbestos or asbestos cloth or paper impregnated with a thermoplastic or similar material or athermo setting type of phenol condensating resin, and still further, to the heat treatment of the friction surface of a clutch element of this kind so as to displace the fluid content at the surface of the impregnated material and to harden said surface or to substantially carbonize the same without rendering such surface-excessively brittle; a furthe! object being to form grooves in the friction surface to reduce the contact area thereof as well as to provide lubricating or other channels in such surface; a further object being to provide a clutch of the class described in the form of a double cone body providing two conical clutch surfaces which are coned or contracted to opposed ends thereof to adapt the clutch for use as a clutch element in tapping attachments and similar devices or apparatus; a still further object being to provide a clutch of the class described which is fashioned from a tubular bodyof asbestos or similar material impregnated and 'heat treated in accordance with the method more fully hereinafter described and claimed.

This application constitutes a division of my application Serial No. 724,110 filed May 5, 1934, and the invention is fully disclosed in the following specification, of which the accompanying drawing forms a part, in which the separate parts of 'my improvement are designated by suitable reference characters in each of the views, and in which: I

Fig.'1 is a sectional view of a clutch unit assemblage indicating one use of the invention, the section being on the line ll of Fig. 2.

Fig. 2 is a section on the line 2-2 of Fig. 1.

Fig.3 is a sectional view of a tubular blank from which a clutch'such as shown in Figs. 1 and 2 is formed.

Fig.4 shows the next step in shaping the blank shown in Fig. 3. Fig. 5 shows the step of heat treating the workpiece.. a

Fig. 6- shows thenext step in forming the clutch. Fig. 7 is a planview of the clutch shown in Fig. 6 indicating the next step in the operation of producing the same; and,

Fig. 8 is a section on the line 8-8 of Fig. 7.

trally of said member.

1934, Serial No.

, For the purpose of illustrating one use of my invention, I have shown in'Figs. l and 2 of the drawing, a clutch unit or assemblage which constitutes apart of the clutch mechanism described and claimed in my U. S. Patent No. 1,988,967,

- dated January 22, 1935.

l2 at right angles to the arrangement of the head ll therein, and the block 12 is rotatable on the pin l3 as well as being movable longitudinally thereof The cylindrical head II is yoke-shaped in form to clear the pin I3 as disclosed in said patent.

At I4, I have shown one of my improved clutch members or facings', and this member is shaped to form conical, clutch or friction faces i5 and I6 subdivided by a circumferential groove l1 cenrality of grooves l8 formed therein to reduce the contact area of the surface If: as well as to provide oil or lubricating channels in such surface, whereas the surface l6 has similar grooves l9 which are less in number than the grooves Hi. The member It has a dove-tailed split 20 at one side thereof to provide for the extension and contraction of said friction member in the use there'- of. A pad or strip 2| of felt or other material is arranged in the split 20 to act as a distance piece and also to aid in supporting the lubricant when employed in conjunction with the clutch.

The member I4 is provided with a bore 22 extending therethrough at;right angles to the split 20 for receiving the pin 13. This pin is held against displacement by a spring-ring 23 which seats in the groove l-l, the ring 23 also serving to hold the felt strip 2| against displacement. In

I the bore of the-member it is a split tube 24 preferably composedof spring material, and this tube is apertured toweceive. the pin l3 and serves to normally hold the member id in extended position, and at the same time, permits the contraction of said member under pressure against the tension of the split tube 24. It will be noted that the split of the'tube 24 is disposed opposite the split 20. in the member ll.

In forming the member ll herein specifically described, I first start with a tube 25 of wrapped or pressed fibrous material impregnated with a thermo setting material in the class of synthetic resins, phenols and the like. For the purpose of The facing i5 has a plu--- giving one illustration, the tube may be composed of asbestos cloth or paper impregnated with a thermoplastic material or a thermo setting material in the class of synthetic resins or phenols. After producing this tube of a desired length and thickness, .the same is shaped to form temporary conical friction surfaces l5 and IS, a groove I! as well as the bore or aperture 22.

After forming the tubular blank 25 in the manner indicatedin Fig. 4 of the drawing, I place in the bore 26 thereof, a rod or mandrel 21 which serves as a means of handling the workpiece as well as a cool agent for the inner wall structure of the workpiece when subjecting it to the heat treatment of a heater ring or other heating element 28. In this connection, if desired, means'may be provided for cooling the mandrel. This ring or element may be composed of castiron, nichrome or other material.

In forming the member [4 herein disclosed, the heating element 28 is heated to approximately 1400 Fahrenheit, and is removed from a heating furnace and the member i4 is placed in the ring 28 so that one friction surface l5l'6 is disposed in engagement with the conical heating chamber 28a of the element 28 in the manner indicated-in Fig. 5, to subject such surface to the heat of the ring. This heat treatment takes but a short period of time, and during the treatment, the fluid contained at the surface of the member being treated will be drawn from said surface and discharged through the lower open.

end 28b of the element 28, and the heat treated surface will be converted into a relatively hard coating or layer which might be termed a carbonizatlon of the surface to such a degree asto provide a smooth hard surface which is reinforced, strengthened and supported by the fibrous body of the member as a whole. The depth or thickness of the treated surface will depend upon the degree of treatment as well as other characteristics of the impregnated fibrous material employedr In Fig. 1 of thedrawing, the stippling at lia, lBa indicated the heat treated outer surface. I

After one surface ,of the member M has been treated, the other surface thereof will be treated in a similar manner, it being desirable to allow the member to cool slightly between each treatment. By using a series of mandrels as well as anumber of theheating elements 28 employed, a successive series of heat treating operations may be performed on different workpieces. After both beveled surfaces I5, I 6 of the member ll have been heat treated, the same are round or otherwise finished to the desired size and contour. The next step in the method con-.

sists in forming the grooves l8 and IS in the surfaces I! and I8, and then the member ll issplit in the annular manner indicated at 20 in Fig. 7 of the drawing so as to provide a substantially dove-tailed recess between adjacent-cut or; split ends of the tubular member or body ll to receive the pad 2|. 4

The member I is now complete and ready for. assemblage of the spring sleeve 24 and spindle i0 therewith as well as the pin'li, pad and ring II. It will be understood that the impregnation of the member II with fibrous material employed therein is relatively slight, that is to say, there is no excessive amount of synthetic resins or other impregnating material employed beyond the saturating point.

'It will therefore be seen that in the heat treattreated friction surface.

ment above referred to and in removing the fluid of the impregnating substance from the surface of the member l4, what remains on the surface is the fibrous material and a part of said impregnating substance in the form of a hard, it smooth surface body or facing which in its characteristics gradually fades into the normal fibrous saturated body constituting the core or inner body structure of said member, thus providing a resilient oryielding support which eliminates to a large degree the possibility of chipping, flaking or cracking, and maintains substantially the full strength and toughness of the original body. The heat treated surface having been subjected to relatively high degrees of heat 13 will adapt the member 54 to the normal or any excess heat which may prevail in its operation as a friction element without destruction or change in the characteristics of said preformed and heat 'ularly where the friction member operates in oil or is subjected to exposure to a lubricant, and various other changes in and modifications of the construction and method herein disclosed may be made within the scope of the appended claims without departing from the spirit of my invention or sacrificing its advantages.

-Having fully described my invention, what I claim as new and desire to secure by Letters Patent, is:

1. The method of manufacturing friction elements which consists in providing a unitary mass of heat resisting fibrous material including a binder of permanently set thermoplastic material, and then locally applying heat treatment to a surface of said element to reduce the thermoplastic material at such surface to carbon for a predetermined depth of said element without impairing or destroying the fibrous material of 4| said body at said surface thereof.

2. The method of manufacturing friction elements which consists in providing a unitary laminated asbestos sheet body bound with a phenol condensating resin binder, fabricating the body thus formed to the desired shape, then locally heat treating a surface of said body to be utilized as the friction surface to reduce the binder at such surface to carbon throughout a predetermined depth of the body without impairingthe asbestos material employed, and then finish shaping and forming said body.

3. The method of manufacturing tubular friction members which consists in wrapping or winding a strip containing asbestos material, and Q a thermoplastic substance in the form of a tube, compressing and treating the same to form a tubular body, beveling one surface of the resultant 1 tubular body to form the approximate contour of tubular body to form the approximate contour of a desired friction surface, then subjecting said friction surface to a temperature sufllcient to reduce the thermoplastic substance to carbon for a predeteed depth on said friction surface without pairing or weakening said body, and then splitting the resultant ,tube longitudinally thereof.

5. The method of manufacturing I tubular friction members which consists in wrapping or windinga strip containing asbestos material and a thermoplastic substance in the form of a tube, compressing and treating the same to form a tubular body, beveling one surface of the resultant tubular body to form the approximate contour of a desired friction surface, subjecting the friction surface to a temperature sufiicient to reduce the thermoplastic substance to carbon for a predetermined depth on said friction surface without pairing or weakening said body, 1 and then ving said surface at circumferentially spaced The method of manufacturing friction elements which consists inproviding a unitary body of laminated asbestos paper bound with a phenol condensating resin, fabricating the body thus formed to the approximate contour of the desired friction surface, then locally heat treatin the friction surface of said body to reduce the binder at said surface to carbon throughout a predetermined depth of the body without impairing the asbestos material employed, and then finish shaping and treating said body. 7. The method'of manufacturing tubular friction members which consists in wrapping or winding a strip containing asbestos and a thermo setting material in the form ofa tube, compressing v and treating the same to provide a relatively hard tubular body, trimming opposite. end portions of the outer surface of said tubular body to form two, conical, friction surfaces thereon, and then subjecting said conical friction surfaces to a ternperature sufiicient to'reducethe thermo setting material to carbon for a predetermined depth on said friction surfaces.

8. The method of manufacturing tubular friction members which consists in wrapping or winding a strip containing asbestos and a thermo setting material in the form of a tube, compressing and, treating the same to provide a relatively hard tubular body, trimming'opposite end portions of the outer surface of said tubular body to form two conical surfaces thereon,-then subiecting said conical surfaces to a temperature suilicient to reduce the thermo setting material to carbon for a predetermined depth on said surfaces, and then grooving said conical surfaces at circumferential intervals.

9. The method of manufacturing tubular friction members which consists in wrapping or winding a strip containing asbestos and a thermo setting material in the form of a tube, compressing and treating the same to provide a relatively hard tubular body, trimming opposite end portions of the outer surface of said tubular body to form two conical surfaces thereon, then subjecting said conical surfaces to a temperature sufiicient to reduce the thermo setting material to carbon for a predetermined depth on said surfaces, and then finish shaping and treating the body thus formed to produce the desired friction element.

10. The method of manufacturing friction elements which consists in providing a unitary mass of heat resisting fibrous material including a binder of permanently set thermoplastic material, then locally applying heat treatment to a surface of said element to reduce the thermoplastic material at such surface to carbon for a predetermined depth of said element without impairing or destroying the-fibrous material of said body at said surface thereof, and then finish shaping and treating said surface.

11. The method of manufacturing friction elements which consists of providing a unitary mass of heat resisting fibrous material including a binder comprising a material adapted to be car-,

12. The method of manufacturing friction elements which consists in providing a unitary body of laminated asbestos and a carbon containing material used as a binder, fabricating the body to an approximate contour on one surface thereof, then heat treating said surface to reduce the binder at said surface tovcarbon throughout a predetermined depth of the body'without impairing the asbestos material employed.

GEORGE W. EMRICK. 

